1. Field of the Invention
The present invention relates to a pressure plate component group, especially for a motor vehicle friction clutch with automatic wear compensation.
2. Discussion of the Prior Art
Motor vehicle friction clutches are generally constructed in such a way that, in the engaged state, the friction linings of a clutch disk are clamped between the pressure plate of a pressure plate component group and a flywheel. The repeated disengagement and engagement procedures carried out during operation of the clutch cause the friction linings of the clutch disk to become used and worn. As a result, as the age of the clutch increases, the pressure plate, in the engaged state, comes ever closer to the flywheel. Because an energy storage device, for example, a diaphragm spring, acts between the pressure plate and a clutch housing, the increasingly close approach of the pressure plate to the flywheel in the engaged state is accompanied by a corresponding following movement of the energy storage device. This in turn means that the optimal working area once provided for the energy storage device, with respect to its force characteristic, is deviated from, so that the energy storage device can no longer perform its suitable or desired function.
To avoid this disadvantage, it is known to integrate clearance indicators and wear readjustment devices into clutches or pressure plate component groups of this type, so that the wear occurring on the friction linings of the clutch disk during clutch operation can be determined and compensated for, for example, by the axial lengthening of the wear readjustment device, in keeping with the wear that has occurred.
In particular, the provision of a clearance indicator often requires relatively expensive structures, because a way to detect the relative movement between two components that move relative to each other when wear occurs must be created. For example, a frequently used method is to provide an axially movable wear detection pin on the pressure plate. The wear detection pin extends radially outside of the clutch disk in the direction of the flywheel. When wear occurs, and the pressure plate therefore moves closer to the flywheel, the wear detection pin strikes the flywheel and thus detects the wear that has occurred. Such a structure requires that the components that perform this wear detection function be arranged radially outside of the clutch disk. This fact results in a corresponding enlargement of the overall pressure plate component group or of the motor vehicle friction clutch equipped therewith.